Many latex templates have set the margins of the page, so you don’t need to modify them. But sometimes you need to set the margins by yourself. Looking up the relevant information, we find that using the geometry macro package can easily adjust the margins.

\usepackage{geometry}

\geometry{a4paper,scale=0.8}

The above command sets the paper as A4, and the proportion of the page center to the page length is 80%; scale can also be changed to ratio, indicating the proportion of the page margin to the page length. The macro package can also set the top, bottom, left and right margins of the page, for example:

\geometry{a4paper,left=2cm,right=2cm,top=1cm,bottom=1cm}